A problem commonly encountered with such segmented pipe couplings, particularly when assembling such a coupling a relatively inaccessible location, is the tendency or ready ability of one of the coupling segments to rotate angularly relative to the other about the single traction bolt used for securing a pair of coupling segments to each other. This requires the use of both hands of the workman in correctly assembling the coupling segments around the pipe ends, and, the movement of the coupling segments to bring them into coplanar relationship, such as required in order that keys on the inner peripheries of the coupling segments are properly oriented with respect to grooves provided in the pipe ends, or, with respect to projections provided on the pipe ends.
Until such time as the traction bolts or securing members are properly positioned at each end of the coupling segments, the coupling segments can move relative to each other in a random manner, such that longitudinal axis of one coupling segment can become angled with respect to the next adjacent coupling segment. Prior to tightening down of the traction bolts, the interconnection of the respective coupling segments is non-positive and allows such rotational or angling movement, with the consequence that the axes of the respective coupling segments may become angled relative to the axes of the respective pipes, which themselves are probably out of axial alignment pending tightening down of the coupling. If this occurs, then, proper seating of the keys of the coupling on the pipe ends can not be assured.
In order to reduce this problem, segmented couplings have been proposed in which the bolting faces of the bolting pads are oppositely angled outwardly commencing at the location of intersection of the axis of the traction bolt with the bolting faces of the bolting pads, and away from the next adjacent bolting face of the next adjacent coupling.
This permits insertion and partial tightening down of one of the traction bolts by a determined extent prior to assembly of the coupling onto the pipes, and permits one of the coupling segments to be angled relative to the next adjacent coupling segment in order to faciliate its passage around the pipes, subsequent to which the respective coupling segments are moved inwardly into engagement with the pipe peripheries.
This is of great assistance in that it permits the insertion of one of the traction bolts prior to assembly of the coupling on to the pipes, and greatly facilitates the handling of the coupling prior to its being tightened down onto the pipes.
However, the interconnection between the respective coupling segments still remains non-positive, with the ability of one of the coupling segments to rotate about the axis of the interconnecting traction bolt, and into a position in which it is no longer in coplanar relationship with the next adjacent coupling segment.
A typical example of such a segmented pipe coupling in which the bolting pads are outwardly angled to permit relative hinging movement between the coupling segments after insertion of a traction bolt and prior to the tightening down of the coupling is illustrated in U.S. Pat. No. 3,024,046, Frost et al. issued Mar. 6, 1962.